Field of the Invention
The present invention relates to ventilation systems for buildings and more specifically relates to displacement ventilation systems for buildings such as school building, office building, auditoriums, and theatres.
Description of the Related Art
Many studies have shown that poor environments in enclosed spaces, which are primarily due to the effects of indoor pollutants, adversely affect the health, attendance, and performance of room occupants. Moreover, it has been determined that there is a direct link between high concentrations of particular air pollutants and reduced attendance levels. Poor environments may also increase microbiological pollutants associated with higher incidences of asthma and respiratory infections.
Many buildings are ventilated, heated and/or cooled using mixed ventilation systems. Although somewhat effective, mixed ventilation systems typically have a number of problems associated therewith including poor air quality, excessive noise, and lower comfort levels, which may adversely affect the performance levels of individuals occupying a building. These negative factors are particularly problematic when mixed ventilation systems are utilized in school environments, where use of these systems has been shown to adversely the health, performance and attendance of students and teachers.
An alternative ventilation methodology, commonly referred to as displacement ventilation, provides an economical means of delivering a supply of fresh air directly to the occupants of an enclosed space so as to improve the quality of the indoor air environment. In displacement ventilation system, outside air is introduced into a room near the floor and at a relatively low velocity. As the air spreads across the room it contacts one or more heat sources such as room occupants or equipment, and the air rises as it picks up heat from the heat sources located in the room. The warm air that is present in the room ascends in a vertical direction toward the ceiling where it enters a return air duct for being exhausted from the room. Because the incoming supply of air follows a vertical air flow pattern near each occupant, it is less likely that germs will spread horizontally across the room.
In spite of the above advances, there remains a need for improved displacement ventilation systems that improve air quality, minimize noise, reduce costs, and may be readily placed in existing buildings.